Apparatus and method for gas capture during electrolysis

ABSTRACT

In one embodiment of the present invention an electrolytic cell is provided comprising: a containment vessel configured for pressurization; a first electrode; a second electrode; a source of electrical current in electrical communication with the first electrode and the second electrode; an electrolyte in fluid communication with the first electrode and the second electrode; a first gas, wherein the first gas is formed during electrolysis at or near the first electrode; a second gas, wherein the second gas is formed during electrolysis at or near the second electrode; a separator; a first gas collection vessel; and a second gas collection vessel, wherein the separator includes a first inclined surface to direct flow of the electrolyte and the first gas due to a difference between density of the electrolyte and combined density of the electrolyte and the first gas such that the gas substantially flows in a direction distal the second electrode and towards the first gas collection vessel, and wherein the separator includes an second inclined surface to direct flow of the electrolyte and the second gas due to a difference between density of the electrolyte and combined density of the electrolyte and the second gas such that the gas substantially flows in a direction distal the first electrode and towards the second gas collection vessel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Nos. 61/153,253, filed Feb. 17, 2009; 61/237,476, filed Aug.27, 2009; and 61/304,403, filed Feb. 13, 2010, each of which isincorporated herein in its entirety by reference.

BACKGROUND

Renewable resources for producing electricity are often intermittent.Solar energy is a daytime event and the daytimesolar-energy-concentration potential varies seasonally. Wind energy ishighly variable. Falling water varies seasonally and is subject toextended drought. Biomass is seasonally variant and subject to droughts.Dwellings have greatly varying demands including daily, seasonal, andoccasional energy consumption rates. Throughout the world, energy thatcould be delivered by hydroelectric plants, wind farms, biomassconversion and solar collectors is neglected or wasted because of thelack of a practical way to save energy or electricity until it isneeded. Demand by a growing world population for energy has grown to thepoint of requiring more oil and other fossil resources than can beproduced. Cities suffer from smog and global climate changes caused bythe combustion of fossil fuels.

Also, burgeoning demands have developed for hydrogen, oxygen, carbon,and other products that can be provided by thermochemistry orelectrolytic dissociation of feedstocks such as water, biomass wastes,or organic acids derived from biowaste. For example, the global marketfor hydrogen is more than $40 billion, and includes ammonia production,refineries, chemical manufacturing and food processing.

Electro-chemical production of fuels, metals, non-metals, and othervaluable chemicals has been limited by expensive electricity, lowelectrolyzer efficiency, high maintenance costs, and cumbersomerequirements for energy intensive operations such as compressive pumpingof produced gases to desired transmission, storage, and applicationpressures. Efforts to provide technology for reducing these problems arenoted and incorporated hereby in publications such as “HydrogenProduction From Water By Means of Chemical Cycles,” by Glandt, EduardoD., and Myers, Allan L., Department of Chemical and BiochemicalEngineering, University of Pennsylvania, Philadelphia, Pa. 19174;Industrial Engineering Chemical Process Development, Vol. 15, No. 1,1976; “Hydrogen As A Future Fuel, by Gregory, D. P., Institute of GasTechnology; and “Adsorption Science and Technology”: Proceedings of theSecond Pacific Basin Conference on Adsorption Science and Technology:Brisbane, Australia, 14-18 May 2000, By D. Do Duong, Duong D. Do,Contributor Duong D. Do, Published by World Scientific, 2000; ISBN9810242638, 9789810242633.

Electrolyzers that allow hydrogen to mix with oxygen present thepotential hazard of spontaneous fire or explosion. Efforts including lowand high pressure electrolyzers that utilize expensive semi-permeablemembrane separation of the gas production electrodes fail to providecost-effective production of hydrogen and are prone to degradation andfailure due to poisoning by impurities. Even in instances that membraneseparation is utilized, the potential danger exists for membrane ruptureand fire or explosion due to mixing of high-pressure oxygen andhydrogen.

Some commercial electrolyzers use expensive porous electrodes betweenwhich is an electrolytic proton exchange membrane (PEM) that onlyconducts hydrogen ions. (See Proton Energy Company and the ElectrolyzerCompany of Canada.) This limits the electrode efficiency because ofpolarization losses, gas accumulation, and reduction of availableelectrode area for the dissociation of water that can reach theinterface of the electrodes and PEM electrolyte. Along with the limitedelectrode efficiency are other difficult problems including membraneruptures due to the pressure difference between the oxygen and hydrogenoutlets, membrane poisoning due to impurities in the make-up water,irreversible membrane degradation due to contaminants or slightoverheating of the membrane, membrane degradation or rupture if themembrane is allowed to dry out while not in service, and degradation ofelectrodes at the membrane interface due to corrosion by one or moreinducements such as concentration cell formation, galvanic cells betweencatalysts and bulk electrode material, and ground loops. Layering ofelectrode and PEM materials provide built in stagnation of the reactantsor products of the reaction to cause inefficient operation. PEMelectrochemical cells require expensive membrane material, surfactants,and catalysts. PEM cells are easily poisoned, overheated, flooded ordried out and pose operational hazards due to membrane leakage orrupture.

In addition to inefficiencies, problems with such systems includeparasitic losses, expensive electrodes or catalysts and membranes, lowenergy conversion efficiency, expensive maintenance, and high operatingcosts. Compressors or more expensive membrane systems are situationallyrequired to pressurize hydrogen and oxygen and other products ofelectrolysis. Corollaries of the last mentioned problem are unacceptablemaintenance requirements, high repair expenses, and substantialdecommissioning costs.

It is therefore an object of some embodiments of the present inventionto provide an electrochemical or electrolytic cell, and a method of usethereof, for separated production of gases, including pressurizedhydrogen and oxygen, that tolerates impurities and products of operationand address one or more of the problems with current methods set forthabove.

SUMMARY

In one embodiment of the present invention an electrolytic cell isprovided comprising: a containment vessel configured for pressurization;a first electrode; a second electrode; a source of electrical current inelectrical communication with the first electrode and the secondelectrode; an electrolyte in fluid communication with the firstelectrode and the second electrode; a first gas, wherein the first gasis formed during electrolysis at or near the first electrode; a secondgas, wherein the second gas is formed during electrolysis at or near thesecond electrode; a separator; a first gas collection vessel; and asecond gas collection vessel, wherein the separator includes a firstinclined surface to direct flow of the electrolyte and the first gas dueto a difference between density of the electrolyte and combined densityof the electrolyte and the first gas such that the gas substantiallyflows in a direction distal the second electrode and towards the firstgas collection vessel, and wherein the separator includes an secondinclined surface to direct flow of the electrolyte and the second gasdue to a difference between density of the electrolyte and combineddensity of the electrolyte and the second gas such that the gassubstantially flows in a direction distal the first electrode andtowards the second gas collection vessel.

In another embodiment an electrolytic cell is provided comprising: acontainment vessel configured for pressurization; a first electrode;second electrode; source of electrical current in electricalcommunication with the first electrode and the second electrode; anelectrolyte in fluid communication with the first electrode and thesecond electrode; a first gas, wherein the first gas is formed duringelectrolysis at or near the first electrode; a separator; and a firstgas collection vessel, wherein the separator includes an inclinedsurface to direct flow of the electrolyte and the first gas due to adifference between density of the electrolyte and combined density ofthe electrolyte and the first gas such that the gas substantially flowsin a direction distal the second electrode and towards the first gascollection vessel.

In yet another embodiment, a method of improving the efficiency of anelectrolytic cell is provided comprising: providing an electrolyticcell; performing electrolysis in the electrolytic cell wherein a firstgas and a second gas is produced in the electrolytic cell during theelectrolysis; providing a first gas collection vessel distinct from theelectrolytic cell and in fluid communication with the electrolytic cell;capturing the first gas in the first gas collection vessel prior tosubstantial expansion of the first gas; expanding the first gas;capturing work generated from the expansion of the first gas; providinga second gas collection vessel distinct from the electrolytic cell andin fluid communication with the electrolytic cell; capturing the secondgas in the second gas collection vessel prior to substantial expansionof the second gas; expanding the second gas; and capturing workgenerated from the expansion of the second gas.

In yet another embodiment, a method of improving the efficiency of anelectrolytic cell is provided comprising: providing an electrolyticcell; performing electrolysis in the electrolytic cell wherein a gas isproduced in the electrolytic cell during the electrolysis; providing agas collection vessel distinct from the electrolytic cell and in fluidcommunication with the electrolytic cell; capturing the gas in the gascollection vessel prior to substantial expansion of the gas; expandingthe gas; and capturing work generated from the expansion of the gas.

Other features and advantages of the present invention will becomeapparent from the following detailed description. It should beunderstood, however, that the detailed description and the specificexamples, while indicating the preferred embodiments of the presentinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the present inventionwill become apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an electrolytic cell in accordance with an embodiment ofthe present invention.

FIG. 2 shows a magnified view of a portion of the embodiment of FIG. 1.

FIG. 3 shows a variation of the embodiment of FIG. 2.

FIG. 4 shows an electrolytic cell in accordance with an embodiment ofthe present invention.

FIG. 5 a magnified view of an alternative embodiment for a portion ofelectrolytic cell of FIG. 4.

FIG. 6 shows a cross-section of a spiral electrode for use in areversible fuel-cell.

FIG. 7 shows a system for converting organic feedstocks such as thoseproduced by photosynthesis into methane, hydrogen, and or carbondioxide.

DETAILED DESCRIPTION

In order to fully understand the manner in which the above-reciteddetails and other advantages and objects according to the invention areobtained, a more detailed description of the invention will be renderedby reference to specific embodiments thereof.

In one embodiment, an electrolytic cell and method of use is provided.While the electrolytic cell may be used in many applications, it isdescribed in this embodiment for use in the production of hydrogen andoxygen. An electrolytic cell according to the present embodimentprovides for reversible separated production of pressurized hydrogen andoxygen and tolerates impurities and products of operation. Theembodiment further provides the option for operating an electrolysisprocess which comprises the steps of supplying a substance to bedissociated that is pressurized to a much lower magnitude than desiredfor compact storage, applying an electromotive force between electrodesto produce fluid products that have less density than the substance thatis dissociated and restricting expansion of the less dense fluidproducts until the desired pressure for compact storage is achieved.This and other embodiments can improve the energy utilization efficiencyof dwellings such as homes, restaurants, hotels, hospitals, canneries,and other business facilities by operation of heat engines or fuel cellsand to utilize heat from such sources to cook food, sterilize water anddeliver heat to other substances, provide space heating or to facilitateanaerobic or electrically induced releases of fuel for such engines orfuel cells. Moreover, one skilled in the art will appreciate thataspects of the embodiments disclosed herein can apply to other types ofelectrochemical cells to provide similar advantages.

Contrary to conventional electrochemical electrodes which depend largelyupon relatively slow diffusion, convection, and concentration gradientprocesses to produce mass transport and/or deliver ions for productionof desired constituents, the present embodiment provides more efficientmass transport including rapid ion replenishment processes anddeliveries to desired electrodes by pumping actions of low-density gasesescaping from a denser liquid medium as described herein. This assuresgreater electrical efficiency, more rapid dissociation, and greaterseparation efficiency along with prevention of undesirable sidereactions. Increasing the rate and efficiency of ion production anddelivery to electrodes increases the system efficiency and current limitper electrode area.

Referring to FIG. 1, an electrolytic cell 2 in which a container 4 suchas a metallic tube serves as a containment vessel is shown. Optionally,the container 4 may also serve as an electrode as shown in FIG. 1. Aporous electrode such as cylindrical conductive wire screen electrode 8is coaxially located and separated from tubular electrode 4 by anelectrolytic inventory of liquid such as an acid or base. Liquidelectrolyte occupies the interior space of container 4 to the liquid-gasinterface in insulator 24. A layer of plated, plasma sprayed, orcomposited electrode material on a dielectric sleeve or a conductivecylindrical inner liner electrode 4′ (not shown) may be provided withincontainer 4 to serve as an electrically separated element of theassembly to enable convenient replacement as a maintenance item or toserve as one of a number of segmented electrode elements for purposes ofoptional polarity, and/or in series, parallel, or series-parallelconnections. In the present reversible embodiment for the electrolysisof water, electrode 8 may be considered the electron source or cathodesuch that hydrogen is produced at electrode 8, and electrode 4 may beconsidered the anode such that oxygen is produced at electrode 4.Container 4 may be capable of pressurization. Pressurization of thecontents of container 4 is restrained by sealed caps 30 and 46. Support,electrical insulation, and stabilization of components includingelectrode 8, gas separator 10, and electrical connection 32 are providedby dielectric insulator bodies 20 and 24 as shown. Pressurization of theelectrolytic cell 2 can be accomplished by self-pressurization due theproduction of gas(es) during electrolysis, by an external source such asa pump or by any combination thereof.

Separator 10 is configured to be liquid permeable but to substantiallyprevent gas flow or transport from the cathode side of the separator tothe anode side of the separator and vice versa, include substantiallypreventing the flow of gas dissolved in the electrolyte or afternucleation of gas bubbles. Optionally, electrode 8 may be configured toact as separator 10 such that a distinct separator is not necessary.Alternatively, separator 10 may include the electrode 8 or electrode 8may include separator 10. In addition, separator 10 may also include theanodic electrode 4 or anodic electrode 4 may include separator 10.

Insulator 24 is shaped as shown and as needed to separate, collectand/or extract gases produced by electrodes such as 4 and 8 includingutilization in combination with separator 10. In the concentriccylindrical geometry shown, insulator 24 has a central conical cavitywithin which gases released on electrode 8 are collected. Concentricallysurrounding this central cavity is an annular zone that collects thegases released from the surfaces of electrode 4′ or from the inside ofcontainer electrode 4.

Optionally, a catalytic filter 48 may be placed in the upper collectionpassage of 24 as shown. Oxygen that manages to reach catalytic filter 48including travel by crossing separator 10 can be catalytically inducedto form water by reacting with hydrogen, which may then return to theelectrolyte. The vast excess of hydrogen can serve as a heat sink toprohibit the heat released by this catalytic reaction from affecting theelectrolytic cell. Purified hydrogen is supplied at fitting 26 as shown.Similarly it may be preferred to provide a catalytic filter 49 in theupper region of the circumferential annulus that collects oxygen asshown, for converting any hydrogen that reaches the oxygen annulus intowater. Oxygen is removed at fitting 22 as shown. Alternatively, thecatalytic filters may be placed at, near or inside fittings 22 and 26.

In illustrative operation, if water is the substance to be dissociatedinto hydrogen and oxygen, a suitable electrolyte is prepared such as anaqueous solution of sodium bicarbonate, sodium caustic, potassiumhydroxide, or sulfuric acid and is maintained at the desired level asshown by sensor 50 that detects the liquid presence and signalscontroller 52 to operate pump 40 to add water from a suitable sourcesuch as reservoir 42 as needed to produce or maintain the desiredinventory or pressure. Controller 52 is thus responsive to temperatureor pressure control sensor 58 which may be incorporated in an integratedunit with liquid level sensor 50 or, liquid inventory sensor 51 andcontrol pumps 36 and 40 along with heat exchanger 56 which may include acirculation pump of a system such as a radiator or heater (not shown) toreceive or deliver heat. Similarly, a heating or cooling fan maybeutilized in conjunction with such operations to enhance receipt orrejection of heat from sources associated with the electrolytic cell 2.

In some embodiments where the electrolytic cell 2 is to be appliedcyclically, e.g., when surplus electricity is inexpensive and nototherwise demanded, electrolytic cell 2 can be operated withconsiderable variation of the water inventory. At times that surpluselectricity is not available or it is turned off, hydrogen and oxygensupplies may be extracted from container 4 and the system is allowed toreturn to ambient pressure. Ambient pressure water can then be added tofully load the system, which can be provided to have a large annularvolume around the circumference of insulator 24 as may be desired tofacilitate such cyclic low-pressure filling and electrolysis operationsto deliver hydrogen or oxygen at the desired high pressure needed forpressure or chemical energy to work conversions, compact storage, andprovide rapid transfers to vehicles, tools, or appliance receivers.

Upon application of current and generation of voluminous gaseoussupplies of hydrogen and oxygen from a much smaller inventory of liquid,the system may be pressurized as desired and remains pressurized untilthe inventory of water in solution is depleted to the point of detectionby sensors 50 or 51 which enables controller 52 to either interrupt theelectrolysis cycle or to add water by pressure pump 40 from reservoir 42as shown. It may be preferable to add water across a valve such as checkvalve 44 as shown to allow multiple duties or maintenance on pump 40 asneeded.

Referring to FIGS. 1, 2 and 3, FIG. 2 shows one embodiment of theseparator 10 of FIG. 1 in which the separator includes two inclinedsurfaces 14 forming a “V” shape. If the electrolyte is water based,electrons are added to porous electrode 8 such as a woven wire cylinderthrough connection 32 and are removed from container 4 throughelectrical connection 6 to continuously convert hydrogen ions intohydrogen atoms and subsequently diatomic molecules that can nucleate toform bubbles on or near electrode 8. Hydrogen and oxygen bubbles aretypically much less dense than water based electrolytes and arebuoyantly propelled upward. Oxygen bubbles are similarly propelledupward and separated from hydrogen by the geometry of coaxial separator10 as shown in the magnified section view of FIG. 2. The configurationshown in FIG. 2 may be used in any application in which the flow of gasformed during operation of the electrolytic cell 2 is desirable.Further, said separator configuration may be employed in otherconfigurations of electrochemical cells known in the art. Alternatively,if the materials formed during electrolysis is of a higher density thanthe electrolyte, separator 10 may be inverted forming a “Λ” shape.Similarly if one material formed at the cathode by electrolysis is lessdense than the electrolyte and another material formed at the anode ismore dense that the electrolyte, separator 10 may be comprised of aslanted “/” or “\” shapes to deflect the less dense material away fromthe more dense material.

Mixing of hydrogen with oxygen that is released from 4′ or the inside ofcontainer 4 is prevented by a liquid-permeable barrier, separator 10which efficiently separates gases by deflection from the surfaces 12′and 14 which are inclined against oxygen and hydrogen entry, flow, ortransmission as shown. Alternatively, separator 10 may include a helicalspiral that is composed of an electrically isolated conductor or frominert dielectric material such as 30% glass filledethylene-chlorotrifluoroethylene in which the cross section of thespiraled strip material is in a “V” configuration as shown to serve asan electrical insulator and gas separator.

Passageways for fluid travel can be increased as desired to meet fluidcirculation and distribution needs by corrugating the strip occasionallyor continuously particularly at each edge to produce clearance betweeneach layer of the helix, or alternatively at the stack of formed disksthat make up the section shown in FIG. 2 as a magnified corrugations asshown at 13 in section view. It is generally advantageous to have eachof such corrugations undulate about an appropriately inclined radialaxis more or less as shown with respect to axis 15 and 15′. This allowsthe overall liquid-porous but gas-barrier wall thickness of separator 10that is formed to be a desired thickness, for example, about 0.2 mm(0.008″) thick or less.

Separator 10 may be of any suitable dimensions including very smalldimensions and with respect to surface energy conditions sufficient toallow the liquid electrolyte to pass toward or away from electrode 8while not allowing passage of gases because of the buoyant propulsionand upward travel of the gas. An alternative embodiment applicable in,for example, relatively small fuel cells and electrolyzers, is providedby a multitude of closely-spaced flattened threads with the crosssection shown in FIG. 2 in which such threads are woven or adhered tothreads that provide mostly open access of liquids and are disposed inthe mostly vertical direction on one or both sides of the “V” shapedthreads. This allows the overall liquid-porous but gas-barrier wallthickness of separator 10 that is formed to be about 0.1 mm (0.004″)thick or less.

Upward buoyant propulsion deflects gas bubble collisions on the inclinedsurfaces 12 and 14. This feature overcomes the difficulties and problemsof the prior art conventional approaches that cause inefficiencies dueto one or more of electrical resistance, fouling, stagnation, corrosion,and polarization losses. Moreover, some configurations can promoteelectrolyte circulation in concentric layers due to the buoyant pumpingaction of rising bubbles that produces flow of electrolyte upward and,as the gas(es) escape at the top of the liquid, the relatively gas-freeand denser electrolyte flows toward the bottom as it is recycled toreplace the less dense electrolyte mixed with bubbles or includingdissolved gas. A heat exchanger 56 may be operated as needed to add orremove heat from electrolyte that is circulated from the top ofcontainer 4 to the bottom as shown. Pump 36 may be used as needed toincrease the rate of electrolyte circulation or in conjunction with pump40 to add make up water.

In some embodiments high current densities are applied, includingsystems with rapid additions of organic material. In such embodiments,it may be advantageous to circulate the electrolyte with pump 36 whichreturns relatively gas free electrolyte through fitting 28 through line34 to pump 36 to return to container 4 through line 38 and fitting 16 asshown. It may be preferred to enter returning electrolyte tangentiallyat fitting 16 to produce a swirling delivery that continues to swirl andthus synergistically enhances the separation including the action byseparator 10 that may be utilized as described above. Depending upon thepressure of operation, hydrogen is about fourteen times less dense andmore buoyant than the oxygen and tends to be readily directed at higherupward velocity by separator 10 for pressurized collection throughfilter 48 at fitting 26. At very high current densities and in instancesthat electrolytic cell 2 is subjected to tilting or G-forces as might beencountered in transportation applications, the velocity of electrolytetravel is increased by pump 36 to enhance swirl separation and thusprevents gases produced on an anode from mixing with gases produced by acathode.

Some embodiments of non-conductive gas barrier and liquid transmittingembodiments including separator 10 enable much less expensive and farmore rugged and efficient reversible electrolyzers to be manufacturedthan previous approaches including those that depend upon protonexchange membranes to separate gases such as hydrogen and oxygen. In oneaspect, separator 10 can be designed to improve electrolyte flow duringelectrolysis. For example, separator 10 can be configured to promote thespiral flow of ions in liquid electrolyte inventories traveling upwardfrom port 16 to port 28. This assures that each portion of theelectrodes receives freshly replenished ion densities as needed formaximum electrical efficiency. Such electrode washing action can alsorapidly remove bubbles of hydrogen and oxygen as they form on therespective electrodes of the electrochemical cell.

FIG. 3 shows the edge view of representative portions of componentsheets or helical strips of another aspect of separator 10 for providingelectrical isolation adjacent electrodes including flat plate andconcentric electrode structures while achieving gas species separationas described above. In assembly 11, sheets 12′ and 14′ form a crosssection that resembles and serves functionally as that of separator 10.Flat conductive or non-conductive polymer sheet 12′ is prepared withmultitudes of small holes on parallel centerlines that are inclined toform substantial angles such as shown by first angle 15 of approximately35° to 70° angles with the long axis of sheet 12′ as shown. Polymersheet 14′ is similarly prepared with multitudes of small holes onparallel centerlines that are substantially inclined as shown by secondangle 15′ to form approximately 35° to 70° angles with the long axis ofsheet 14′ as shown.

In other embodiments the angles 15 and 15′ can be varied depending onthe material to separated during the electrolysis process. For examplethe angles could be declined, for electrolysis of compounds that have nogaseous constituent or only one gaseous constituent. If a compound suchas Al₂O₃ is dissociated by electrolysis in cryolite-alumina electrolyteto form aluminum and oxygen, the aluminum is more dense than thecryolite-alumina electrolyte and the aluminum separating cathodeelectrode or associated separator would be configured (by, e.g.,declined angles) to send the aluminum downward and away from the oxygentraveling upward.

Multitudes of such small holes with diameters of about 1/12 to ⅓ of thesheet thickness dimension can readily be made in sheets 12′ and 14′ bysuitable technologies including laser drilling, hot needle piercing, orby high-speed particle penetrations. Sheets 12′ and 14′ each of whichare typically about 0.025 to 0.25 mm (0.001″ to 0.10″) thick can be heldtogether by welding or otherwise bonding, thread ties, elastic bands, orone or more spiral wraps of conductive or nonconductive wire on theresulting outside diameter to form as an assembly with electrode 8.Sheets 12′ and 14′ may also be joined occasionally or continuously byadhesives or by thermal or solvent fusion. Thus, where the inclinedholes of sheet 12′ overlap the holes of sheet 14′ passageways are formedto enable liquid and/or electrolyte travel while prohibiting gastransmission through the gas barrier membrane that is formed. Referringto FIGS. 1 and 4, tubular constructions of the assembled gas barriersheets may be formed with the appropriate diameter for embodiments 2 or100 by adhering or welding the butt seam or by providing an overlappedseam that performs as the intended separation gas barrier.

For electrolysis of water, a variety of electrolytes are suitable. Inone embodiment potassium hydroxide may be used with low carbon steel forthe containment vessel 4. Extended life with increased corrosionresistance may be provided by nickel plating cylinder 4 or byutilization of a suitable stainless steel alloy. In other aspects,increased containment capacity can be provided by overwrapping cylinder4 with high-strength reinforcement such as glass, ceramic, or carbonfilaments or a combination thereof.

Depending upon the particular application and strength requirements itmay be advantageous to use about 30% glass filled ethylenechlorotrifluoro-ethylene for insulating separators 20 and 24. Electrode8 may be made of woven nickel or type 316 stainless steel wires.Separator 10 may be made from about 30% glass filledethylene-chlorotrifluoro-ethylene strip.

In another embodiment, it is also intended to utilize controlledapplications of electricity to produce methane or hydrogen separately orin preferred mixtures from organic electrolytes. In some aspects, theembodiment can operate in conjunction with the embodiments of copendingpatent application including Ser. No. 09/969,860, which is incorporatedherein by reference. Anaerobic digestion processes of organic materialsthat ordinarily produce methane can be controlled to produce anelectrolyte that releases hydrogen at considerably lower voltage or by areduced on-time of a pulse-width modulated duty cycle and resultingelectricity expenditure than that required to dissociate water.

Acidity or pH of the organic solution that is produced by microbialdigestion can be maintained by a natural bicarbonate bufferedinteraction. The bicarbonate buffer may be supplemented by co-productionof carbon dioxide in the digestion process. The process may begeneralized for various steps in anaerobic digestion processes oforganic compounds by illustrative digestion of a simple carbohydrate orglucose that may have many competing and complementary process stepssuch as:

C₆H₁₂O₆+(Anaerobic Acid formers, Facultative bacteria)→CH₃COOH  Equation1

CH₃COOH+NH₄HC₆O₃→CH₃COONH₄+H₂O+CO₂  Equation 2

3CH₃COONH₄+3H₂O(Bacteria)→3CH₄+3NH₄HCO₃  Equation 3

In instances that methane from such solutions is desired, pH controlnear 7.0 may be needed. At ambient pressure, pH of about 7.0, and 35-37°C. (99° F.), methanogenesis is favored. Most domestic wastewatercontains biowastes with both macro and micronutrients required by theorganisms that provide methanogenesis. Maintaining relatively largeconcentrations of dissolved and distributed hydrogen or monosaccharidespresent in the anaerobic reactor may inhibit operations ofmethane-forming microorganisms.

In another aspect, increased production of fuel values from organicsubstances can be accomplished by application of an electric field tocause dissociation of substances such as acetic acid (CH₃COOH) that areproduced by bacterial breakdown of glucose and other organic compoundsand by other acid-production processes that yield hydrogen ions.

CH₃COOH→CH₃COO⁻+H⁺  Equation 4

Hydrogen ions migrate or are delivered to the negatively chargedelectrode and gain electrons to produce hydrogen gas.

2H⁺+2e ⁻→H₂  Equation 5

Two electrons are supplied by the negatively charged electrode. At theother electrode the electrochemical reaction includes oxidation of theacetate ion to carbon dioxide and hydrogen ions as summarized inEquation 6.

CH₃COO⁻+2H₂O →2CO₂+7H⁺+Electrons  Equation 6

In this electrode reaction, acetate ions lose electrons, subsequentlyreact with the water and break up into carbon dioxide gas and hydrogenions. Carbon dioxide saturates the solution and is released from theliquid solution interface as set forth in the above embodiments.Hydrogen ions are circulated and/or migrate until electrons are receivedfrom the opposite electrode to produce hydrogen atoms and then diatomicmolecules as summarized in Equation 5 for separate co-collection in suchsystems. Separated collection is highly advantageous, for example,separated collection to cause pressurization or at high pressure as aresult of liquid pumping instead of gas compression, is especiallyefficient and greatly reduces the capital equipment ordinarily requiredto separate and then mechanically compress the hydrogen, methane orcarbon dioxide produced.

Decomposition by anaerobic digestion of compounds such as acetic acid toproduce hydrogen and carbon dioxide requires much less energy thanelectrolysis of water, because, in part, the digestion reactions yieldhydrogen ions and exothermic energy. Initialization and maintenance ofthe exothermic decomposition of acids such as acetic acid may beaccomplished at lower voltage applications or by intermittent oroccasional electrolysis instead of continuous electrolysis as typicallyrequired to decompose water. The free energy of formation of water atambient temperature is quite large (at least 1 KWH=3,412 BTU of releasedhydrogen) compared to the electrolysis of digester substances and acidssuch as urea and acetic acid to hydrogen and carbon dioxide, whichrequires relatively minimal activation and/or catalytic actionparticularly by organic catalysts. Accordingly, selected catalystsincluding modifications to Raney-Nickel catalysts, nickel-tin-aluminumalloys, selections from the platinum metal group, platinum-nickel andother platinum-transition metal single crystal alloy surfaces, andvarious organic catalysts utilized in conjunction with the electrodesystems set forth herein further improve the rate and/or efficiency ofhydrogen production.

In another aspect, it may be preferred to utilize numerous cells ofelectrode pairs connected in switchable series or parallel orseries-parallel for purposes of matching the available source amperageand voltage with the voltage required for dissociation by seriesconnection of cells such as shown in FIG. 1. In one aspect of thisembodiment, each cell may require about 0.2 to 2 volts depending uponthe aqueous electrolyte chosen or biochemically produced from organicsubstances so a home-size 6-volt photovoltaic source could have 3 to 30cells in series and an industrial 220-volt service may have about 100 to1,000 electrode cells connected in series. Product gases could readilybe delivered by parallel or series collection arrangements. Dependingupon the desired flexibility for adjusting the number of series and/orparallel connections, support and flow control feature 18 may be by aninsulating or non-insulating material selection.

At various current densities, including at medium and low currentdensities, it may be preferred to allow buoyant propulsion of thebubbles that are generated to accomplish circulation of the electrolyteto prevent ion depletion and stagnation problems. At start-up or highercurrent densities one can operate pump 36 and heat exchanger 56 toprovide the desired operating temperature and presentation of ion-richelectrolyte at the electrode surfaces. This enables extremely high ratesof energy conversion in which energy such as off-peak electricityavailable from solar, wind, falling water, or wave resources is utilizedto quickly and efficiently produce high-pressure supplies of oxygen andhydrogen or hydrogen and carbon dioxide or hydrogen and methane alongwith carbon dioxide for separated storage and use.

In one aspect of this embodiment, the problem of regenerative braking ofvehicles or power-plant spin-down in which sudden bursts of largeamounts of energy must be quickly converted into chemical fuel potentialis addressed. A conventional fuel cell for truck, bus, or trainpropulsion cannot tolerate high current densities that are suddenlyapplied to the fuel cell electrodes. This embodiment overcomes thislimitation and provides extremely rugged tolerance of high currentconditions while achieving high electrolysis efficiency without theproblems of PEM degradation or electrode-interface failures thatregenerative PEM fuel cells suffer. Because of the rugged constructionand extremely ample opportunities for cooling that are provided,extremely high current operations are readily accommodated. Conversely,this embodiment readily starts up and operates efficiently in severecold or hot conditions without regard for various PEM-relateddifficulties, limitations, and failures.

In another aspect, in order to achieve much higher return on investmentin energy conversion systems such as a hydroelectric generating station,wind farm, system of wave generators, or conventional power plants, theembodiment allows off-peak electricity to be quickly and efficientlyconverted into hydrogen and oxygen by dissociation of water or hydrogenand carbon dioxide by dissociation of substances generated by anaerobicdigestion or degradation of organic matter. A compact version of theembodiment can occupy a space no larger than a washing machine andconvert off-peak electricity that might otherwise go to waste intoenough hydrogen to operate two family size vehicles and provide theenergy requirements of the home.

As set forth above, some embodiments provided herein provide moreefficient mass transport including rapid ion replenishment processes anddeliveries to desired electrodes by pumping actions of low-density gasesescaping from denser liquid medium. This assures greater electricalefficiency, more rapid dissociation, and greater separation efficiencyalong with prevention of undesirable side reactions. Increasing the rateand efficiency of ion production and delivery to electrodes increasesthe system efficiency and current limit per electrode area. Applicationsthat convert organic substances into carbon dioxide and hydrogen ormethane are particularly benefited by: enhanced rates of delivery oforganic substances to microorganisms that participate in the process,incubation and delivery of incubated microorganisms to extend andself-repair biofilm media, more rapid separation of produced gases anddelivery of organic substances along with more efficient delivery ofintermediate ions to electrodes.

Referring to FIG. 4, another embodiment, electrolytic cell 100 is shownthat is particularly beneficial in applications in which it is notdesired to apply voltage or to pass current through the inside walls ofcontainment vessel 102. The embodiment also facilitates seriesconnections of bipolar or multiple electrode sets or cells such as 110and 114 within the electrolytic cell 100 to simplify gas collection andvoltage matching needs.

In one aspect in which that containment vessel 102 is cylindrical andthe components within are concentric, electrode assemblies 110 and 114may be formed from numerous nested truncated conical components or oneor both electrodes may be formed as a helical electrode as describedabove. Electrodes 110 and 114 may be of the same, similar or differentconfigurations. In another aspect, electrode 114 may be assembled fromnested truncated conical sections or it may be a spiral electrode thatcontinuously encircles electrode 110.

Electrical separation of electrodes 110 and 114 to prevent shortcircuits may be accomplished by various means including by controlledtolerances for the operating dimensions and/or by the use of dielectricthreads or filaments placed between electrodes 110 and 114 and/or byanother form of separator 10 or 111 as disclosed regarding FIGS. 2 and5.

The electrolytic cell 100 may be pressurized. Pressure containment isprovided by upper and lower caps 104 and 106 as shown. Insulators 120and 122 are supported by caps 104 and 106 as shown. The circuitcomponents and hardware for electrical and fluid connections areillustrative and can be accomplished by penetrations through caps 104and 106 as needed to meet specific application needs.

In the current embodiment, both electrodes 110 and 114 are formed tohave inclined surfaces that direct the substance produced such as gasreleased to respective collection zones as shown. Illustratively, ifwater is to be dissociated from a suitable electrolyte, electrode 110may receive electrons that are supplied through connection 108, which issealed in cap 106 by plug seal 132. Electrons are thus taken fromelectrode 114 through plug seal 130, which provides insulation ofcontact 124 as a gas such as carbon dioxide or oxygen is released onelectrode 114.

Such gases are thus propelled by buoyant forces and travel more or lessupward as delivered by electrode 114 and along the inside wall ofcontainer 102. Hydrogen is propelled upward as delivered by electrode110 and within the center core formed by numerous turns or conicallayers of electrode 110 and collected as shown at insulator 120.Purified hydrogen at design pressure is delivered by pressure fitting116. Catalytic filter 134 may be used to convert any oxidant such asoxygen that reaches the central core to form water. A similar catalyticfilter material may be used to produce water from any hydrogen thatreaches the outer collection annulus in insulator 120 as shown.Pressurized filtered oxygen is delivered by pressure fitting 118.

Optionally, to improve the efficiency of the electrolytic cell 100, oneor more gas collection vessels (not shown) may be in fluid communicationwith electrolytic cell 100 to collect gas formed during electrolysis.The gas collection vessel can be implemented to capture the gas at anelevated pressure prior to substantial expansion of the gas. The gascollection vessel can be further configured to capture work as the gasexpands according to methods known in the art. Alternatively, the gascollection vessel can be configured to provide gas at pressure forstorage, transport or use wherein the gas is desired to be delivered atan elevated pressure. It is further contemplated that said aspect can beimplemented in various electrochemical cells.

Referring to FIG. 2, in another aspect, a gas expander may be includedat, near or inside fitting 22, fitting 26 or in a gas collection vesselin fluid communication with fitting 22 or fitting 26. Similarly,referring to FIG. 4, a gas expander may be included at, near or insidefitting 116, 118 or in a gas collection vessel in fluid communicationwith fitting 116 or fitting 118.

In another aspect, a method and apparatus for electrolysis to pressurizea fluid coupled with a device to extract work from such pressurizedfluid is provided. The fluid may be pressurized liquid, liquid-absorbedgas, vapor or gas. Conversion of pressurized fluid to vapor or gas mayoccur in or after fitting 116 and a device to convert the pressure andflow from such fittings could be selected from a group including aturbine, generator, vane motor, or various piston motors or an enginethat breathes air and injects pressurized hydrogen from 116. Similarlyconversion of pressurized fluid to vapor or gas could be in or afterfitting 118 and a device to convert the pressure and flow from suchfittings could be selected from a group including a turbine, generator,vane motor, or various piston motors or an engine that expands and/orcombusts pressurized fluid such as oxygen from 118.

In another aspect, an apparatus and method to overcome the high cost andpower losses of a transformer and rectifier circuit is provided. This isaccomplished by adjusted matching of load voltage with source voltage byseries connection of electrode cells or electrodes within a cell, suchas connecting the negative polarity of a DC source to the lowest threeturns of electrode 110 to the next three turns of electrode 114 to thenext three turns of electrode 110 to the next three turns of electrode114 and to the next three turns of electrode 110 et seq. and startingfrom the opposite (highest) end to connect the positive lead from the DCsource to three turns of electrode 114 to the next three turns ofelectrode 110 to the next three turns of electrode 114 to the next threeturns of electrode 110 to the next three turns of electrode 114 et seq.Turns and/or stacks of truncated cones may be adjusted to develop thearea needed to match the source amperage.

In another aspect of this embodiment, in addition to providingseparation of the gases produced by electrolysis, the pumping actiondeveloped by the invention provides for delivery of nutrients tomicroorganisms that, depending upon the relative scale of operations,are hosted in suitable media such as carbon cloth, activated carbongranules, expanded silica, graphite felt, coal, charcoal, fruit pits,wood chips, shredded paper, saw dust, and/or mixtures of such selectionsthat are generally located within portions of electrode 110 and/orbetween portions of electrode 114 and container 102. Correspondingfunctions and benefits include thermal stabilization of the system,circulation of feedstocks and removal of products such as carbon dioxideand production of hydrogen from acids that may be produced by theincubation, nutrition, and growth of such microorganisms.

At low and medium current densities, buoyant forces induced by lowdensity solutions and bubbles can circulate the electrolyte withincontainer 102. At higher current densities it is advantageous toadaptively control temperature, pressure, and circulation of theelectrolyte as previously disclosed. External circulation of electrolytemay be from fitting 126 to fitting 138 as shown and includes situationsin which one or numerous electrode cells connected in optional seriesand/or series-parallel circuits are contained within container 102.

In another aspect, the embodiment can be optimized for high currentdensities to deliver commensurately higher electrolyte fluid flow ratesthrough one or more holes or grooves 139, which direct fluid at atangent to the annular space between electrodes 110 and 114. Electrolyteflows upward along the helical spaces formed by the electrodes and isreplenished by electrolyte entering helical paths provided by 110 and114 from the annular space between 110 and 114. The angular momentum ofthe electrolyte entering the space between electrodes 110 and 114increases the impetus of bubble lift pumping by electrolytic productssuch as hydrogen and oxygen respectively produced on electrodes 110 and114 and adds to such momentum.

This circulation of electrolyte is highly beneficial for purposes ofassuring rapid replacement of ions that become hydrogen and oxygen atomsor other gases such as carbon dioxide upon charge exchanges to and fromelectrodes 110 and 114 and for removing such gases for collection andremoval with minimum electrical polarization loss during electrolysis.Thus very high current densities are readily accepted to efficientlyelectrolyze the circulated fluid. In another aspect, furtheraccommodation of high current densities is provided by the vast coolingcapacity of the design resulting from improved electrolyte circulation,which prevents harmful stagnation of products of electrolysis and/orphase changes such as steam nucleation, and reduction of effectiveelectrode areas.

In another aspect, electrodes 110 and 114 may constitute spring formsthat can be advantageously operated at a resonant frequency or perturbedby various inducements including piezoelectric drivers, rotatingeccentrics, and the action of bubble formation and the accelerationthrust by less-dense mixtures of electrolyte and bubbles as higherdensity electrolyte inventories are delivered to the surfaces ofelectrodes 110 and 114 by the pumping action that results. In responseto perturbation, electrodes 110 and 114 vibrate at natural or inducedfrequencies to further enhance dislodgement of bubbles from surfacesincluding nucleation sites and thus enable higher current densities andgreater energy-conversion efficiency.

Induced vibration of helical spring-form electrodes such as 110 and 114can also cause peristaltic mechanical action to enhance bubbleacceleration toward the respective collection paths and exit ports ofelectrolytic cell 100. During this vibration, cyclic increases anddecreases of the average distance and angle between adjacent layers ofelectrode turns produce fixed or traveling nodes depending upon themagnitude and frequency of the inducement(s).

FIG. 5 shows a representative section view of a set of electrodes 110′and 114′ for operation in conjunction with an electrically insulativespacer 111 between 110′ and 114′ including selections such as insulator10 shown in FIG. 2 that includes a helical flow delivery configurationfor various applications or electrolytes. The assembly of concentricelectrode 110′, spacer 111, and electrode 114′ provides a very rugged,self-reinforcing system for enabling efficient dissociation of fluidssuch as water, liquors from anaerobic digesters, or seawater withimproved efficiency and resistance to fouling. Electrodes 110′ and 114′may be constructed from conductive carbon papers, cloth, or felt; wovenor felt carbon and metal filaments, graphite granules sandwiched betweenwoven carbon or metal filaments; or metal-plated polymers or metallicsheet stocks such as mild steel, nickel plated steel, or stainless steelthat are drilled more or less as previously disclosed with multitudes ofholes on parallel centerlines that are inclined as shown for respectiveseparations of hydrogen from co-produced gases such as oxygen, chlorine,or carbon dioxide depending upon the chemical make up of theelectrolyte.

In instances that electrode 110′, spacer 111, and electrode 114′ areutilized in concentric electrode deployments such as shown in FIG. 4,hydrogen is delivered to port 116 and depending upon the substanceundergoing dissociation, products such as oxygen, chlorine or carbondioxide delivery is provided at port 118. In some instances it ispreferred to provide the multitude of holes in 110′ and 114′ such thateach hole is slightly tapered from the hole diameter on surfacecontacting spacer 111 to a larger diameter at the exit surface away fromspacer 111.

It is preferred to select the helical pitch, width between electrodes,and thickness of the strip comprising spacer 111 for delivery ofelectrolyte from 138 to and through electrodes 110′ and 114′ to fitting126 at rates that are commensurate with the electrical power availableand the system heat transfer requirements to optimize the resultingwidth space between electrodes. This results in abundant deliveries ofions for electrolysis processes at electrodes 110′ and 114′ whileassuring separation of hydrogen to the zone within electrode 110′ anddelivery of co-produced gases such as oxygen, carbon dioxide, orchlorine to the space outside of electrode 114′.

In another aspect, it is possible to operate the system regenerativelyby providing gas flow grooves in the hydrogen electrode and gas flowgrooves in the oxygen electrode along with appropriate fittings foradding hydrogen to the bottom of the hydrogen electrode and oxygen atthe bottom of the oxygen electrode. In this case it may be advantageousto utilize concentric spiral electrodes particularly in small fuel cellswhere a single canister assembly meets energy needs.

Referring to FIG. 6, a cross-section of a spiral electrode(s) for use ininstances that reversible fuel-cell operation is shown. This providesimprovement of the surface to volume ratio, section modulus, and columnstability of electrode 114 or of a similar helical version of electrode110. Electrode 114 is illustrated in the section with gas 152 flowingalong spiral grooves formed by corrugating the strip stock that is usedto form the spiral and provide delivery of oxygen for fuel-celloperation and in electrolysis operation to deliver oxygen to annulus 136and fitting 118. The same configuration works well for electrode 110 infuel-cell and electrolysis modes for conversion of organic acids intocarbon dioxide and hydrogen and in the electrolysis mode and assuresplentiful gas delivery to the desired collection or source ports aspreviously described.

In another aspect, improved electrode performance is provided byfacilitating the growth and maintenance of microorganisms that convertaqueous derivatives of organic substances such as carbonic, acetic,butyric and lactic acids along with compounds such as urea intohydrogen. On the electrode chosen for production of hydrogen ions and/orthe release of carbon dioxide, increased microbe productivity isfacilitated by preparing such electrode surfaces with topographicalenhancements that increase the effective surface area including highaspect ratio filaments or whiskers that reduce electrical resistance tothe substrate electrode and help hold microbes and biofilm in placealong with the desired film substances provided by digestive processes.

Without being limited by theory, it is believed that the specificfeatures of the electrode and/or separator, such as the topographicaltreatments or enhancement, promote turbulence, including cavitation orsuper cavitation, of the electrolyte at a desired location which in turnpromotes nucleation at the location. Conversely, the specificconfiguration of the electrode and/or separator can inhibit turbulence,including cavitation or super cavitation at a desired location, forexample, the point of electron transfer, which in turn inhibitsnucleation at that location. It is contemplated that elements includingthese features can be implemented at any location in the electrolyticcell at which nucleation is desired. Moreover these same features andprinciples can be applied to a gas collection vessel or similar in fluidcommunication with the electrolytic cell, or to fluid communication withpassages or valves there between.

Suitable filaments and or whiskers include metals or dopedsemiconductors such as carbon, silicon or nano-diameter filaments ofcarbon or boron nitride to provide increased surface area, reduceion-transport and ohmic loses, increased microbe productivity and moreeffective nucleation activation for more efficient carbon dioxiderelease. Such filaments may also be utilized to anchor graphite granulesthat further improve microbe productivity, enhanced efficiency of enzymeand catalyst utilization, and related beneficial hydrogen ion productionprocesses. Similarly, at the electrode where hydrogen ions are providedwith electrons to produce hydrogen atoms and nucleate bubbles ofdiatomic hydrogen, filaments and whiskers may be utilized to increasethe active area and reduce the voltage required for the overall process.

In addition to carbon whiskers, filaments grown from metals such as tin,zinc, nickel, and refractory metals deposited from vapor or grown fromplating on suitable substrates such as iron alloy electrodes, have beenfound to provide reduced electrical resistance and improved processefficiency. Such filaments or whiskers may be made more suitable forbiofilm support and process enhancement by addition of conducivesurfactants and or surface plating with suitable substances such ascarbon, boron nitride, or silicon carbide deposited by sputtering orfrom decomposition of a substance such as a carbon donor fromillustrative precursors such as acetylene, benzene, or paraffinic gasesincluding methane, ethane, propane, and butane.

The embodiment of FIG. 4 and variation thereof can provide advantageousseparation of low density gaseous derivatives of fluid dissociationincluding hydrogen separation from organic liquors as summarized inEquations 1-6 to deliver hydrogen or selections of hydrogen-enrichedmixtures to port 116 while carbon dioxide or carbon dioxide enrichedmixtures including fixed nitrogen components are delivered to port 118.In some applications it may be desirable to reverse the polarity ofthese electrodes to reverse the delivery ports for gases that areseparated. Such reversals may be long term or intermittent to accomplishvarious purposes. Depending upon selections of helical pitch(es) ofelectrodes 110 and 114 and each electrode's resonant or imposedfrequency of vibration, and the relative fluid velocity at eachelectrode, hydrogen may be delivered to port 116 but the system may beoperated to include methane and carbon dioxide. However, carbon dioxidedelivered to port 118 may include methane and other gases of greaterdensity than hydrogen. In applications that it is desired to provideHy-Boost mixtures of hydrogen and methane to enable unthrottledoperation of internal combustion engines, various burners, furnaces orfuel cells, the embodiment of FIG. 4 operating with hydraulic andelectrical circuit control provisions such as provided by pump 36 andcontroller 52, facilitates the option of producing and separatingdesired fuel mixtures with controlled ratios of hydrogen and methane fordelivery at port 116.

An unexpected but particularly beneficial arrangement for production ofvigorous anaerobic colonies of microbes that produce the desiredconversion of organic feedstocks to hydrogen and/or methane is providedby adding media such as colloidal carbon, carbon filaments includingnanostructures, exfoliated carbon crystals, graphene platelets,activated carbon, zeolites, ceramics and or boron nitride granules tothe electrochemical cell. Such media may be doped or compounded withvarious agents to provide enhanced catalytic productivity.Illustratively, desirable functionality may be provided by doping withselected agents having electron structures more or less like boron,nitrogen, manganese, sulfur, arsenic, selenium, silicon, tellurium, andor phosphorous. Circulation induced by the gases released by theelectrolysis process can promote sorting of such media into advantageouslocations and densities for more efficient charge current utilization.

Without being limited to a particular theory, it is hypothesized thatsuch synergistic results relate to increased surface areas in criticallocations and development of stringers, regions, or filaments thatenhance nucleation processes and or conduct electrons or hydrogen ionsalong with advantageous adsorption of enzymes, hydrogen, methane orcarbon dioxide in biofilms and reaction zones that result. It is alsoindicated that microbes are incubated for circulation to efficientlyutilized locations in the operations performed and flow paths producedin various embodiments disclosed herein.

In addition to whiskers and filaments such as carbon, graphite, variousmetal carbides, and silicon carbide and other inorganic substances andparticles that catalytically enhance performance, it is beneficial toutilize activated substances and particles that present desirednutrients or catalysts to assist microbial processes. Illustratively,porous and/or exfoliated substrates of polymers, ceramics or activatedcarbon may adsorb conductive organic catalysts such asco-tetramethoxyphenylporphirine (CoTMPP) orpoly(3,4-ethylenedioxythiophene) (PEDOT) and or favorably orient andpresent other catalytic substances including enzymes and graft polymersthat may also be utilized to incorporate and present catalyticsubstances including additional enzymes.

Suitable substances or graft polymers may include those of conventional,dendrimers, fiberforms, and other organic functional materials tominimize or replace platinum and other expensive catalysts andconductors. Such replacement substances and their utilization includesmixtures or staged locations with respect to the fluid circulationresulting from some embodiments disclosed herein. Variously specializedconductive and or catalytic structures include acicular deposits andfibers that may be grown or attached to the electrodes 4, 8, 110, or 114and/or to overlaid carbon felts or woven structures or dispersed intodeveloping biofilms. Illustratively, conductive and/or catalyticfunctionalities may be provided by filaments that retain and presenthydrogenase and other enzymes, CoTMPP and or other catalysts such aspoly(3,4-ethylenedioxythiophene) (PEDOT) as fibers that are synthesizedfrom aqueous surfactant solutions as self-organized thin-diameter,nanofibers with an aspect ratio of more than 100 and provide lowresistance to charge conductivity. Synthesis in aqueous solutionsincluding anionic surfactant sodium dodecyl sulfate (SDS) can be adaptedto produce various configurations by changing the concentrations of SDSand furthermore by adding FeCl₃ to produce polymerized structures. (Anexemplary procedure is described in Moon Gyu Han et al., FacileSynthesis of Poly(3,4-ethylenedioxythiophene) (PEDOT) Nanofibers from anAqueous Surfactant Solution, Small 2, No. 10, 1164-69 (2006),incorporated herein by reference.) Other examples include functionalcatalysts and micro-conductors in the form of nanocomposites derivedfrom cellulose nanofibers and semiconducting conjugated polymersincluding polyaniline (PANI) and a poly(p-phenylene ethynylene) (PPE)derivative with quaternary ammonium side chains. Cellulose, carbon orceramic whiskers with anionic surface charges carp be combined withpositively, charged conjugated polymers to form stable dispersions thatcan be solution cast from polar solvents such as formic acid.

Preparations include graft polymers and end caps of organometallicalkoxides, metal alkyls and application of the catalytic benefits ofacetic acid and a polymeric catalyst containing COOH end group. Specialfunction and bifunctional end groups along with mixtures of end groupsmay be chosen to produce multi-functional characteristics includingcatalytic functions, reactive stabilizers, grafting agents, andpromoters of dispersion polymerization. Similarly, specializedactivation of carbon or other substrates by hydrogen and or enzymesproduced by anaerobic microorganisms provides a locally hydrogen-richenvironment to enhance or depress methane production and enhanceadditional hydrogen production from various organic substances.

Referring to FIGS. 1-3, optionally it may be advantageous to provide oneor more supplemental felts and or woven screens of carbon filaments tothe outside and inside surfaces of cylindrical components 8, 10, 11,110, and or 114. Such supplemental felts and or woven screens maycommensurately collect or distribute electrons in conjunction withelectrodes 4, 8, 110, and or 114 and or separators 10 or 11 and helpanchor or preferentially locate granules, filaments, and or otherstructures to reduce pressure losses or more equally distribute liquorflows and facilitate microbial functions in the desired energyconversion operations.

Among the complementary and competing reactions and processes to providenet production of hydrogen and carbon dioxide are various steps ofprocesses summarized in Equation 8.

Carbon+2H₂O→CO₂+4H⁺+4Electrons  Equation 8

Carbon is consumed as summarized in Equation 8 including carbon that maybe supplied as a constituent or a carbonaceous substance mixed withliquor from an anaerobic digester or electrolyzer or as a result ofvarious manufacturing outcomes. Illustratively, carbon may include scrapfrom grinding, machining, electro-discharge-machining (EDM), and variousthermochemical operations to produce electrodes, electrode coatings onelectrodes including tank liners, or particles, or filaments, orflocculants, or selected carbides by thermal dissociation and reactionprocesses, including colloidal or other suspensions as an outcome ofvarious degrees of dehydrogenization of organic substances.

Such carbon and/or carbon-donor feedstocks may be renewably supplied bybacteria, phytoplankton, or larger algae that receive carbon dioxide andother nutrients from the liquor supplied or by circulation of carbondioxide to hydroponic and or soil-supported plants. It is advantageousto utilize such forms of carbon with high surface to volume ratios andto provide a voltage gradient to zones where they are delivered for thepurpose of driving the reaction indicated and for delivering hydrogenions to electrode surfaces including complementary conductive media suchas filaments and conductive filter substances for production,nucleation, and release of hydrogen bubbles to increase the overall rateof hydrogen production.

Suitable provisions for increasing active surfaces and or flocculantsinclude those with organic constituents such as bacteria, proteins,simple and complex sugars, cellulose, thermally dissociated cellulose,live and dissociated phytoplankton along with various forms of colloidalcarbons, activated carbons, and carbides. Illustratively, phytoplanktonand or larger algae may be grown, dried, mixed with a binder such ascorn syrup, thermally dehydrogenated to various extents and milled toprovide finely divided flocculants. Alternatively, activated carbonfeedstocks may be milled to provide finely divided particles that areutilized as enzyme receivers or flocculent media or it may be used inconjunction with the previously disclosed substances to enhance thedesired production or efficiency of enzymes, to support incubation ofdesired microorganisms, or to increase hydrogen or methane productionand or consumption of carbon to produce hydrogen ions for electrolysisas indicated by Equation 8.

If needed, occasional use of salt water or additions of small amounts ofsalt to water-based electrolytes can produce chlorine to quicklydisinfect or to prevent harmful fouling of the electrolyzer systemsshown. Utilization of some embodiments, for example FIG. 5, enables theresulting system to be inherently free of harmful fouling even whenutilizing electrolytes such as wastewater, commercial process water,wood-ash water, sea water, fly-ash water, canal and ditch water, oranaerobic digester liquor. Further, such systems can be quickly cleanedif needed by backflow of electrolyte or cleaning water from fitting 118to 138 to dislodge particles that may have been delivered to theelectrodes.

Applications of some embodiments include large community waste disposaloperations to nano-size electrolyzers, include improvements toconventional waste digesters from which solutions or “liquor” containingorganic substances is supplied for production of hydrogen and/or methaneand or carbon dioxide and other plant nutrients. In this capacity someembodiments can provide rapid and efficient conversion of byproductsproduced by anaerobic digesters and convert hydrogen ions into hydrogenand overcome acid degradation of the methane production operations. Inoperation, liquor from an anaerobic digester is utilized to producehydrogen and carbon dioxide to provide beneficial restoration and ormaintenance of pH near 7.0 instead of more acidic conditions that maystymie methane production systems. This enables increased overall energyconversion efficiency as it overcomes the requirement for expensiveprovisions for addition of chemical agents to adjust the pH indigesters. In such medium and large applications it is beneficial todesign and engineer multifunctional components including electrondistribution circuits that may also provide desired retention ofgranules such as carbon, boron nitride, zeolites, polymers, and ceramicsincluding such substances in variously activated conditions for enhancedperformance.

In another aspect, an electrolyzer such as disclosed herein may beapplied to provide rapid conversion of acids that are typically producedby anaerobic digestion including applications with municipal waste waterand landfills along with wastes form slaughter houses, dairies, eggfarms, and other animal feeding centers or similar. Production ofmethane is slowed or inhibited if acids that are produced by anaerobicconditions cause the pH to fall much below 7. Such acids can form if thefeed rate of organic material exceeds the capacity of the methanogeniccolony of microorganisms. By extracting hydrogen from such acids therate of organic material processing by anaerobic digestion can beincreased. The combination of methane and hydrogen provides much greaternet energy production per ton of wastes, and the wastes are processedfaster to increase the capacity of the process.

A particularly useful embodiment of the some embodiments is inwaste-to-energy applications that utilize organic substances such assewage along with hydrolyzed garbage, farm wastes, and forest slash inthe anaerobic electro-digestion process summarized in Equations 1-6 toproduce hydrogen with minimal or no oxygen production. The ruggedconfiguration and recirculation operations enable great tolerance fordissolved solids including organic solids and particles in anaerobicprocess liquors that are utilized as electrolytes. Production ofhydrogen without commensurate release of oxygen as would be released byelectrolysis of water facilitates higher efficiency and safety forutilization of the waste-sourced hydrogen as a cooling gas in electricalequipment such as an electricity generator.

In another application of some embodiments disclosed herein,electrolyzer system 900 as shown in FIG. 7 provides for tissue and/orcellular disruption of biomass by enzyme, mechanical, thermal, acoustic,electrical, pressure and/or chemical actions and processes inconditioner 950 to enable faster or more complete processing, digestionand/or support of incubator purposes. Fluid including such disruptedcells from conditioner 950 and related feedstocks that are produced byconverter 902 is circulated to electrolyzer 914 through annulardistributor 922 of base 910 as shown. Anaerobic microorganisms aresupported by media 940 and 942 and receive liquid recirculated fromhydrogen separator 904 through conduit 910 and liquid recirculated fromcarbon dioxide separator 906 through conduit 908 as shown. Electrode 918and/or media 942 releases hydrogen and electrode 916 and/or media 940releases carbon dioxide. Electromotive bias is provided to electrodes916 and 918 through circuit 926 by source 924 which may range from 0.1to about 3 VDC depending upon the compound dissociation requirement andoccasional needs for increased voltage to overcome insulating films thatform. Hydrogen is ducted to collection and delivery to separator 904 bytravel along the more or less conical surface 925, which may be aconductive surface depending upon the desired series/parallel variationsor contained and supported by insulator 930 as shown.

In operation, liquors are mingled in distributor annulus 922 and travelupwards to provide process reactants and nutrients to microorganismshosted in activated carbon cloth and/or granules 940 and 942 and orconductive felts that encase and substantially retain such granulesproximate to electrode 916 and or 918. Smaller particles and filamentsmay be added to infiltrate locations throughout the electrolyzer systemto enhance electrical charge conductivity, enzyme, and catalyticfunctions including those previously disclosed. Separator 902 may be areverse osmosis membrane or a cation or anion exchange membrane or itmay be constructed according to the embodiments shown in FIG. 2, 3, 4,or 5 and in some instances such separators may be used in conjunctionwith each other as may be desired to provide for various liquorcirculation pathways and/or to produce hydrogen and carbon dioxide atdifferent pressures or with a pressure differential between hydrogen andcarbon dioxide.

Similarly, numerous circulation options are available if electrode 916along with adjacent felt and or media 940 operate as electron sources toproduce hydrogen from ions delivered from liquors that are circulated bythe action of gas production lifts, convection currents, or by pumpdeliveries as shown. In this option, carbon dioxide is released ashydrogen ions are produced from acids delivered from 902 and 950 or thatare produced by microorganisms hosted in fibrous or granular media 942and associated felt materials that are electrically biased by electrode918 to be opposite to electrode 916 as shown. Another exemplary optionresults if electrons are supplied by electrode 918 to produce hydrogenthat is collected by insulator 930 for delivery to gas collector 904 asshown. In this instance electrode 916 and the media electricallyassociated with it are electron collectors as carbon dioxide is releasedto provide pumping in the fluid circuit shown as carbon dioxide isdelivered past insulator 930 to collector 906 as shown.

Referring to FIG. 7, system 900 can be used for converting organicfeedstocks such as those produced by photosynthesis into methane,hydrogen, and/or carbon dioxide and/or by microorganisms. Depending uponthe microorganisms that are hosted, liquors that typically include acidssuch as acetic and butyric acids along with compounds such as urea aredissociated in electrolyzer 914. Electrolyzer 914 provides current atsufficient voltage to produce hydrogen from such compounds and acids andmay provide operation as a digester and an electrolyzer, or may beoperated within an anaerobic digester (not shown) or may utilize liquorsproduced by anaerobic digestion in 914 as shown. Such operation isparticularly useful for converting organic wastes from a community andor industrial park for purposes of supplying the community with fuel andfeed stocks for manufacturing carbon enhanced durable goods.

Although the invention has been described with respect to specificembodiments and examples, it will be readily appreciated by thoseskilled in the art that modifications and adaptations of the inventionare possible without deviation from the spirit and scope of theinvention. Accordingly, the scope of the present invention is limitedonly by the following claims.

1. An electrolytic cell comprising: a containment vessel configured forpressurization; a first electrode; a second electrode; a source ofelectrical current in electrical communication with the first electrodeand the second electrode; an electrolyte in fluid communication with thefirst electrode and the second electrode; a first gas, wherein the firstgas is formed during electrolysis at or near the first electrode; asecond gas, wherein the second gas is formed during electrolysis at ornear the second electrode; a separator; a first gas collection vessel;and a second gas collection vessel, wherein the separator includes afirst inclined surface to direct flow of the electrolyte and the firstgas due to a difference between density of the electrolyte and combineddensity of the electrolyte and the first gas such that the gassubstantially flows in a direction distal the second electrode andtowards the first gas collection vessel, and wherein the separatorincludes an second inclined surface to direct flow of the electrolyteand the second gas due to a difference between density of theelectrolyte and combined density of the electrolyte and the second gassuch that the gas substantially flows in a direction distal the firstelectrode and towards the second gas collection vessel.
 2. Theelectrolytic cell of claim 1 wherein the first gas collection vessel isconfigured to capture work produced by expansion of the first gas andthe second gas collection vessel is configured to capture work producedby expansion of the second gas.
 3. The electrolytic cell of claim 2wherein the first gas comprises hydrogen.
 4. The electrolytic cell ofclaim 2 wherein first gas comprises hydrogen and the second gascomprises oxygen.
 5. The electrolytic cell of claim 4 further comprisinga filter configured substantially remove impurities prior to capturingthe first gas in the first gas collection vessel.
 6. The electrolyticcell of claim 5 wherein the filter comprise a catalytic material.
 7. Theelectrolytic cell of claim 1 wherein the separator comprises the firstelectrode.
 8. An electrolytic cell comprising: a containment vesselconfigured for pressurization; a first electrode; a second electrode; asource of electrical current in electrical communication with the firstelectrode and the second electrode; an electrolyte in fluidcommunication with the first electrode and the second electrode; a firstgas, wherein the first gas is formed during electrolysis at or near thefirst electrode; a separator; and a first gas collection vessel, whereinthe separator includes an inclined surface to direct flow of theelectrolyte and the first gas due to a difference between density of theelectrolyte and combined density of the electrolyte and the first gassuch that the gas substantially flows in a direction distal the secondelectrode and towards the first gas collection vessel.
 9. Theelectrolytic cell of claim 8 wherein the gas collection vessel isconfigured to capture work produced by expansion of the first gas. 10.The electrolytic cell of claim 9 further comprising a filter configuredto substantially remove impurities prior to capturing the first gas inthe first gas collection vessel.
 11. The electrolytic cell of claim 10wherein the filter comprises a catalytic material.
 12. The electrolyticcell of claim 9 wherein first gas comprises hydrogen.
 13. Theelectrolytic cell of claim 9 wherein the separator comprises the firstelectrode.
 14. A method of improving the efficiency of an electrolyticcell comprising: providing an electrolytic cell; performing electrolysisin the electrolytic cell wherein a first gas and a second gas isproduced in the electrolytic cell during the electrolysis; providing afirst gas collection vessel distinct from the electrolytic cell and influid communication with the electrolytic cell; capturing the first gasin the first gas collection vessel prior to substantial expansion of thefirst gas; expanding the first gas; capturing work generated from theexpansion of the first gas; providing a second gas collection vesseldistinct from the electrolytic cell and in fluid communication with theelectrolytic cell; capturing the second gas in the second gas collectionvessel prior to substantial expansion of the second gas; expanding thesecond gas; and capturing work generated from the expansion of thesecond gas.
 15. The method of claim 14 where the first gas compriseshydrogen.
 16. The method of claim 14 where the first gas compriseshydrogen and the second gas comprises oxygen.
 17. The method of claim 16where the first gas collection vessel is substantially free of oxygenand the second gas collection vessel is substantially free of hydrogen.18. The method of claim 17 further comprising the step of filtering thefirst gas to substantially remove the second gas prior to capturing thefirst gas in the first gas collection vessel.
 19. The method of claim 18wherein the step of filtering comprising reacting the second gas to formwater to substantially remove the second gas prior to capturing thefirst gas in the first gas collection vessel.
 20. A method of improvingthe efficiency of an electrolytic cell comprising: providing anelectrolytic cell; performing electrolysis in the electrolytic cellwherein a gas is produced in the electrolytic cell during theelectrolysis; providing a gas collection vessel distinct from theelectrolytic cell and in fluid communication with the electrolytic cell;capturing the gas in the gas collection vessel prior to substantialexpansion of the gas; expanding the gas; and capturing work generatedfrom the expansion of the gas.
 21. The method of claim 20 where thefirst gas comprises hydrogen.
 22. The method of claim 21 where the stepof capturing the gas in the gas collection vessel prior to substantialexpansion of the gas comprises capturing hydrogen substantially free ofimpurities.
 23. The method of claim 22 further comprising the step offiltering the gas prior to capturing the gas in the gas collectionvessel.